1. Field of the Invention
The present invention relates to electronic apparatus including a rotary unit that is rotated horizontally relative to a main unit.
2. Description of the Related Art
A compact electronic apparatus, for example, a portable cellular phone or a personal digital assistant is generally of a fold-down type and comprises a movable unit serving as a display unit that has a liquid crystal display screen and a main unit serving as a keyboard unit to input numbers and characters. In recent years, a portable cellular phone having a display unit that can be rotated 180° horizontally to a keyboard unit has made its debut. With the display unit closed, the keyboard unit is located under the display unit. When the portable cellular phone is opened, the display unit and keyboard unit are disjoined from each other at an angle of 180°. Unlike the fold-down type, the rotary type has the display unit thereof oriented forward. If the keyboard is not required to enter a phone number, telephoning or e-mail can be performed with the portable cellular phone left closed. Moreover, if the portable cellular phone includes a camera facility, the large display unit serves as a viewfinder. Moreover, if the portable cellular phone includes a facility for receiving television, viewing and listening can be achieved with the display unit left closed. The rotary type portable cellular phone is therefore expected to be widely adopted in the future.
The display unit of the portable cellular phone and the keyboard unit thereof are electrically connected to each other with a hinge between them. The fold-down type portable cellular phone adopts a flexible printed circuit (FPC) board having numerous signal lines printed on a flexible insulating plate (refer to Japanese Unexamined Patent Application Publication No. 2004-47968). However, the rotary type portable cellular phone whose display unit is rotated has signal lines, which pass through a shaft support via which the display unit is pivoted, twisted 180°. If the flexible printed circuit board is twisted through an angle exceeding 90°, a load on the flexible printed circuit board increases. This brings about the risk of breakage. Therefore, the flexible printed circuit board cannot be disposed in a place where the flexible printed circuit board may be twisted 180°. Consequently, there is difficulty in disposing the flexible printed circuit board in the shaft support for the purpose of electrically connecting the display unit and keyboard unit. Therefore, signal lines formed with thin cables are bundled and passed through the hinge in order to electrically connect the display unit and keyboard unit.